Cloud Computing is the ability to use the power of other computers (located somewhere else) and their software, via the Internet (or sometimes other networks), without the need to own them. They are being provided to you, as a service.
Google as an example of cloud computing
What happens when you type and search something on Google?
Have you ever thought about this? Does your PC goes through all that information, sorts it out for you and display all the relevant results? No, it doesn’t. Otherwise, you would wait much longer for a simple results page to display. A simple PC can’t process all those billions of websites in a fraction of a second, like Google does. Your PC only serves as a messenger to tell Google what you are looking for. Everything else is done by some of Google’s powerful computers located somewhere, Who-Knows-Where in the world.
Now, did you ever care about how or where that comes from? Why would you, right? Exactly. That’s a great example of how cloud computing is used.